1. Field of the Invention
The present invention relates to an improved refrigerating circuit
2. The Prior Art
The refrigerant drying path, which is incorporated in a closed refrigerating circuit, and which is usually designed as a filter and conducts liquid refrigerant, has the task of extracting any residual moisture and possible fine dirt particles and abrasion particles of the drying means from the liquid refrigerant in order to insure dryness and stability of the circuit.
In the case of known refrigerating circuits, the refrigerant drying path is formed by a separate drier or filter-drier, which is incorporated into the closed circuit by soldering, or by a fluid-tight connection, and has a capillary or expansion valve disposed upstream of a flow throttle point with respect to the flow direction of the liquid refrigerant.
These driers or filter-driers essentially consist of a housing in which a drying means and a sieve, are provided downstream of the drying means in the flow direction of the refrigerant. One end of the housing is matched to the diameter of the pipe of the condenser, and the other end is matched to the diameter of a capillary or an expansion valve connected thereto.
This mode of construction of the drier, which is commonly used in a refrigerating circuit for a refrigerating and freezing appliance with a rear wall condenser, is expensive to produce. This is due to the housing requiring an increased diameter and a consequent narrowing at the inlet and outlet ends to match, respectively, the diameter of the pipe of the rear wall condenser, and the diameter of the capillary. Moreover, connecting the drier with the condenser pipe and the capillary is an expensive step, which has to be carried out with particular care in order to avoid impairment of the circuit. In the case of driers of that kind, the inlet end and the outlet end must be closed securely after manufacture and until assembly in order to prevent an ingress of air moisture or small dirt particles so as to ensure full effectiveness of the drier after incorporation into the refrigerating circuit. The ingress of small dirt particles and moisture into the drier before incorporation into the circuit would also significantly impair the dryness and stability of the circuit.
In German patent DE 297 14 545 U1, there is disclosed a refrigerating circuit in which the drying means is introduced in the form of loose material into an enlargement of the pipe. This pipe carries the liquid refrigerant of the rear wall condenser, which is separated by a sieve from the adjoining capillary, or is inserted as a filter cartridge, which is to be filled with drying means with a filter sieve. Although additional incorporation of a drier can be dispensed with for a refrigerating circuit of that kind, and the disadvantages connected therewith can almost be excluded, the enlargement of the pipe of the rear wall condenser is expensive. Moreover, the production effort and care during the assembly, for example during the soldering of the capillary, continue to be required, so that costs can not be substantially improved using this refrigerating circuit.
In known refrigerating circuits of a larger stationary refrigerating plant, the filter drier, which is added to the refrigerating circuit, consists of a housing containing solid bodies of filter drying agent, which are produced as pressed sintered bodies of a filter drying agent. These solid bodies, also known as filter drying cartridges, are clamped together by special fastening equipment so that they are flowed through in succession by refrigerant within the housing of the filter drier. The fastening equipment, wherein the filter drying cartridges must be connected together and mounted within the housing, are relatively expensive. The length of this fastening equipment must be matched to the number of the filter drying cartridges used. Consequently, an associated fastening equipment must be kept in reserve for each filter drier of a certain capacity.
Moreover, the drier must be protected against the ingress of moisture and dirt particles by closing the entry and exit openings up to its time of assembly into the refrigerating circuit.
A refrigerating circuit for an air-conditioning plant with a condenser, in which drying means equipment in the form of a filter cartridge for integration within the condenser in the flow path of the refrigerant, is known from German patent DE 198 00 739. This filter cartridge consists of a filter drying means which, similarly as for a drier, is introduced into a cylindrical projection of a housing, which is capable of being screwed into place. The thus-formed drying equipments is inserted into the liquid refrigerant flow of a collecting pipe of the condenser. This refrigerating circuit, due to the additionally insertable drying equipment, has almost the same disadvantages as outlined for the preceding refrigerant circuits. Due to the formation of the condenser with deflecting stages, the length of the drying equipment and thus the surface of the drying means flowed across by liquid refrigerant is limited, whereby the dryness and the stability of the circuit can be impaired.
There is therefore a need to improve such refrigerating circuits so that the effectiveness of the circuit can be increased by using a component carrying liquid refrigerant, and a separate component, which is to be incorporated into the circuit, with a drying or filtering function that can be dispensed with, so that manufacturing and assembly costs can be reduced.